JP5736627B2 - Lithium secondary battery cooling system - Google Patents

Description

  The present invention relates to a lithium secondary battery used in a portable electric / electronic device, a hybrid vehicle (HEV), an electric vehicle (EV), and the like, and in particular, a lithium secondary battery in which cooling of the lithium secondary battery proceeds promptly. The present invention relates to a cooling method and a cooling system.

  Recently, compact and lightweight electric / electronic devices such as mobile phones, notebook computers, and camcorders have been actively developed and produced. Such a portable electric / electronic device or the like has a built-in battery module so that it can operate even in a place where a separate power source is not provided. The built-in battery module includes at least one battery therein so that a voltage of a certain level can be output in order to drive the portable electric / electronic device for a certain period.

  In consideration of economical aspects, the battery module has recently adopted a secondary battery that can be charged and discharged. Among them, lithium secondary batteries with high energy density and operating voltage and excellent life characteristics are widely used as energy sources for various mobile devices as well as various electronic products.

  In addition, lithium secondary batteries are electric vehicles (EVs) and hybrid vehicles (represented as alternatives to solve environmental pollution and global warming problems such as existing gasoline vehicles and diesel vehicles using fossil fuels). It is also attracting much attention as an energy source such as HEV) and is in the stage of commercialization.

  Lithium secondary batteries have an operating voltage of 3.6V, which is three times higher than nickel-cadmium batteries and nickel-hydrogen batteries, which are often used as power sources for portable electronic equipment, and have a high energy density per unit weight. It tends to stretch rapidly on the side.

  Generally, lithium secondary batteries are classified into liquid electrolyte batteries and polymer electrolyte batteries according to the type of electrolyte. Secondary batteries using liquid electrolyte are called lithium ion secondary batteries, and secondary batteries using polymer electrolyte. Is called a lithium polymer secondary battery. Furthermore, secondary batteries are classified into cylindrical batteries, prismatic batteries, and pouch batteries according to the external and internal structural characteristics, and can be stacked with a high degree of integration, and have a small width compared to the length. In particular, a pouch-type battery that is light in weight is also attracting attention.

  Lithium secondary batteries mainly use a lithium-based oxide as a positive electrode active material and a carbon material as a negative electrode active material. That is, the lithium secondary battery is disposed between a positive electrode plate coated with a positive electrode active material, a negative electrode plate coated with a negative electrode active material, and a short circuit between the positive electrode plate and the negative electrode plate. An electrode assembly wound with a separator that enables only movement of (Li-ion), a secondary battery exterior material that accommodates the electrode assembly, and injected into the secondary battery exterior material It consists of an electrolyte that enables the movement of lithium ions.

  Such a lithium secondary battery is formed by laminating a positive electrode plate coated with the positive electrode active material and connected with a positive electrode terminal, a negative electrode plate coated with a negative electrode active material and connected with a negative electrode terminal, and a separator. The electrode assembly is manufactured by winding.

  Thereafter, the electrode assembly is accommodated in the outer packaging material for a lithium secondary battery so that the electrode assembly is not detached, and an electrolyte is injected into the outer packaging material for the lithium ion secondary battery, and then sealed. Thus, a lithium secondary battery is completed.

  In the battery module including a large number of unit cells that can be charged and discharged, one of the most problematic matters is safety. The safety problem of the battery module is induced by deterioration of module components due to heat generation, external impact, etc., and internal short circuit.

  In other words, if a large number of unit cells are stacked, the degree of filling is high, but there is a drawback that it is difficult to remove the heat generated during charging and discharging, and heat is not accumulated and accumulated. In this case, the battery is deteriorated and not only the life is shortened, but also safety can be greatly impaired. In particular, batteries that require high-speed charging and discharging characteristics, such as power sources for electric vehicles and hybrid vehicles, generate a large amount of heat in the process of providing high output instantaneously. Is even bigger.

  In other words, if the unit cell heat generated during the charging and discharging process cannot be removed effectively, heat accumulation will occur, resulting in deterioration of the unit cell, and in some cases, ignition or explosion. Therefore, a cooling system is essential.

  In the case of a secondary battery, a large number of positive electrodes / separation membranes / negative electrodes are laminated. However, in the existing case, externally after absorbing heat generated from the battery with a heat sink attached to one side surface of the secondary battery However, until the heat transfer is advanced to the heat sink through the various layers of the positive electrode / separation membrane / negative electrode, the cooling rate is reduced.

  The present invention is for solving such problems of the prior art. An object of the present invention is to provide a cooling means on one side of a battery so that the internal temperature rises due to abnormal heat generation of the battery. An object of the present invention is to provide a cooling method and a cooling system for a lithium secondary battery, in which the inside of the battery is suppressed from rising above a predetermined temperature, and thus is thermally cooled to improve the thermal safety.

  In order to solve the above-described problems, the present invention provides a method for cooling a lithium secondary battery in which a connector is connected to an electrode terminal of a secondary battery, and a coolant is brought into contact with the connector to cool a battery cell.

  Furthermore, the present invention provides a cooling system for a lithium secondary battery including a conductive connector fixed to an electrode terminal and a refrigerant pipe connected to the connector and through which a refrigerant flows.

  The connector includes a body, a fixing part formed on one side of the body and connected and fixed to an electrode terminal, and a connecting part formed on the other side of the body and connected to a refrigerant pipe.

  Alternatively, the connection tool may include a body fixed to the electrode terminal and a connection part through which the refrigerant pipe is connected through the body.

  At this time, the fixing portion is fixed to the electrode terminal by welding.

  The refrigerant is a fluid and may be water or air, and the refrigerant pipe may be made of synthetic resin (made of synthetic resin), but is not limited thereto.

  According to the present invention, a cooling means is provided on one side of the secondary battery, and when the internal temperature rises due to abnormal heat generation of the secondary battery, the inside of the secondary battery is prevented from rising above a predetermined temperature, and thus quickly. Cooling can improve the thermal stability of the secondary battery.

  Furthermore, since the present invention includes a cooling means on one side of the secondary battery, it is not necessary to provide a separate cooling pin.

  Further, in a secondary battery including a large number of unit batteries, even if the space between the unit batteries is narrow or the unit batteries are arranged in contact with each other, an increase in the internal temperature of the secondary battery can be prevented. Therefore, the secondary battery of the present invention can minimize the volume as compared with the conventional secondary battery.

1 is a schematic diagram showing a first embodiment of a cooling system for a secondary battery according to the present invention. FIG. 3 is a schematic diagram showing a second embodiment of a cooling system for a secondary battery according to the present invention. FIG. 5 is a schematic diagram illustrating a third embodiment of a cooling system for a secondary battery according to the present invention.

  Hereinafter, preferred embodiments of a cooling method and a cooling system for a lithium secondary battery according to the present invention will be described with reference to the drawings.

  The secondary battery applied to the present invention may be a single unit battery, or may be a battery module in which two or more unit batteries are stacked together. The term “battery module” used in the present specification is a structure of a battery system that can mechanically fasten and electrically connect two or more unit batteries and provide electricity of high output and large capacity. Is comprehensively included, and includes all cases in which one apparatus is configured as a whole or a part of a large apparatus. For example, a configuration of a battery pack in which many battery modules are connected is also possible.

  As described above, the secondary battery may be formed by stacking one or two or more unit cells to form a battery module. However, one or two or more unit cells may be exposed at the outermost part thereof. The battery module can be configured by stacking a plurality of cartridges attached to a cartridge that can be incorporated in a state. In particular, when a pouch-type battery that has low mechanical rigidity and is not easily electrically connected to an electrode terminal or the like is used as a unit battery, the battery module is preferably attached to a cartridge.

  On the other hand, a unit cell or the like constituting a battery module (in particular, a medium- or large-sized battery module) is a secondary battery that can be charged and discharged, and the unit cell in the present invention may be a secondary battery that can be charged and discharged. There is no particular limitation. For example, a lithium secondary battery, a nickel-hydrogen (Ni-MH) secondary battery, a nickel-cadmium (Ni-Cd) secondary battery, and the like can be given. A battery can be preferably used. Among these, in terms of the shape of the unit battery, a rectangular battery and a pouch battery are preferable, and a pouch battery having a low manufacturing cost and a low weight is more preferable.

  Such a secondary battery generates a large amount of heat indispensable during the operation process. If such heat is not efficiently removed, the secondary cell promotes deterioration of the unit cell and, in some cases, induces ignition or explosion. It can happen.

  Accordingly, in the present invention, in order to more quickly cool the heat generated from the battery cells, heat is transmitted through at least one of the positive electrode terminal and the negative electrode terminal. In the secondary battery cooling method according to the above, heat generated from the battery cells is cooled using an air-cooled or water-cooled refrigerant.

  That is, the heat generated from the inside of the battery is transferred to the electrode terminal, and the transferred heat is transmitted through one of the positive electrode terminal and the negative electrode terminal or a connection tool connected to the negative electrode terminal. Will be done. Thereafter, the connector is quickly cooled by coming into contact with air or water.

  Meanwhile, a cooling system for implementing the above-described secondary battery cooling method is shown in FIGS.

  As illustrated, the cooling system according to the present invention includes a conductive connector 20 having one end fixedly coupled to the electrode terminal 11 of the lithium secondary battery 10, and a secondary battery 10 connected to one side of the connector 20. And a refrigerant pipe 30 that cools the heat transferred to the connector 20.

  In the present invention, the unit cell of the secondary battery 10 is a pouch-type unit cell, and the electrode assembly having a positive electrode / separation membrane / negative electrode structure is connected to the electrode terminal 11 formed outside the cell exterior member. It is built in.

  That is, electrode terminals (a positive electrode terminal and a negative electrode terminal) that are electrically connected to the electrode assembly protrude from the cell exterior material. The electrode terminal 11 or the like may be formed to protrude only in one direction on one side or the other side of the cell outer packaging material, or may be formed to protrude in both directions on all of one side and the other side.

  The connector 20 may be any one as long as the heat transferred from the battery cell of the secondary battery to the electrode terminal can be transmitted to the refrigerant tube 30 side. High metal (made of metal) can be used.

  More specifically, the metal having high thermal conductivity includes copper (Cu), aluminum (Al), platinum (Pt), gold (Au), nickel (Ni), zinc (Zn), cobalt (Co), One or more selected from the group consisting of iron (Fe) and alloys thereof can be used, but is not limited thereto.

  As shown in FIGS. 1 and 2, the connector 20 includes a body 21 having a predetermined length, a fixing portion 23 formed on one side of the body 21 and connected and fixed to the electrode terminal 11, and the other side of the body 21. It may be configured to include a connecting portion 22 formed to be connected to the refrigerant pipe 30.

  At this time, it is preferable that the fixing portion 23 is fixedly coupled to the electrode terminal 11 but is fixed by welding so as not to hinder heat transfer while being firmly fixed.

  Since the connecting portion 22 is provided so as to intersect the body 21, the connecting tool 20 has an overall “T” shape, and the connecting portion 22 protruding on both sides of the body 21 can contact the refrigerant. The refrigerant pipe 30 is coupled.

  Further, the connector 20 'may be configured more simply as shown in FIG. In other words, by comprising the body 21 ′ and the connecting portion 22 ′ formed through the body 21 ′, the aforementioned fixing portion is omitted, and the body 21 ′ is directly fixed to the electrode terminal 11 by welding. Is.

  When the connector 20 ′ is simply configured as described above, the distance from the electrode terminal 11 to the refrigerant pipe 30 can be shortened to further increase the effect of heat transfer, and thus the battery cell can be more quickly formed. There is an advantage that it can be cooled.

  The refrigerant pipe 30 is formed of an empty hollow body, and a refrigerant such as air or water flows inside the refrigerant pipe 30. The part where the refrigerant pipe 30 is coupled with the connector must be firmly fixed so that the refrigerant does not leak. For example, a separate sealing member such as an O-ring or a sealing liquid may be further provided at a coupling site between the connector and the refrigerant pipe. The refrigerant pipe 30 may be manufactured in a straight line as shown in FIGS. 1 and 3, or in order to maximize the circulation time of the refrigerant in a limited space and increase the cooling efficiency of the battery cell. As shown in FIG. 2, it may be manufactured in a zigzag form.

  On the other hand, if the refrigerant tube 30 is made of a conductive material, when the internal temperature of the secondary battery rises rapidly, a short circuit inside the battery occurs due to contact with the connector 20. . Such a short circuit causes considerable danger such as explosion of the secondary battery. Therefore, the refrigerant pipe 30 is preferably made of a synthetic resin or the like in order to reduce the overall weight while preventing the short circuit from being caused by the contact with the connector 20.

  More specifically, the synthetic resin may be one or more selected from the group consisting of chloroprene rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, nitrile-butadiene rubber, and mixtures thereof. However, it is not limited to this.

  The refrigerant will move inside the refrigerant pipe 30, and the type of refrigerant is not particularly limited as long as it can remove the heat of the battery cell as a fluid moving through the flow path, Preferably it may be air or water.

  The driving means for moving the refrigerant can vary according to the type of refrigerant, and when the refrigerant is air, it can be a cooling fan, preferably driven by a motor.

  As described above, when a large number of unit cells are stacked in a battery module, the battery module has a high degree of filling, but it is required to effectively remove heat generated during charging and discharging. The present invention is consistent with this point, and heat generated from the battery cell is transmitted through the electrode terminals, and is quickly cooled using a refrigerant, so that the unit battery generated during the charging and discharging process can be used. It is possible to effectively remove heat and prevent deterioration of the unit battery due to heat accumulation.

10 Secondary battery 11 Electrode terminal
20, 20 'coupling 21, 21' body
22, 22 'connecting part 23 fixing part
30 Refrigerant pipe

Claims (11)

A cooling system for a lithium secondary battery having an electrode terminal,
Conductive couplings respectively fixed to a plurality of electrode terminals formed on both side surfaces of the cell exterior material;
Refrigerant pipes that are hollow in the interior so that the refrigerant is circulated by connecting the conductive couplers respectively.
With
The refrigerant pipe is
One side is connected to a conductive connector fixed to an electrode terminal formed on one side surface of the cell exterior material, and the other side is an electrode formed on the other side surface opposite to the one side surface of the cell exterior material. Connected to a conductive connector fixed to the terminal,
The conductive connector is
Body,
A fixing portion formed on one side of the body and connected and fixed to the electrode terminal;
A cooling system for a lithium secondary battery, comprising a connecting portion formed on the other side of the body and having both ends connected to the refrigerant pipe .   2. The cooling system for a lithium secondary battery according to claim 1, wherein the connection part is formed with a hollow having both ends opened so that a refrigerant flows into and out of the connection part. The fixed portion is formed by welded to the electrode terminals, cooling system of a lithium secondary battery according to claim 1 or 2. A cooling system for a lithium secondary battery having an electrode terminal,
Conductive couplings respectively fixed to a plurality of electrode terminals formed on both side surfaces of the cell exterior material;
Refrigerant pipes that are hollow in the interior so that the refrigerant is circulated by connecting the conductive couplers respectively.
With
The conductive connector is
A body fixed in contact with the electrode terminal;
A cooling system for a lithium secondary battery, comprising a connecting portion penetrating the body and having both ends connected to the refrigerant pipe . The connecting part is formed with a hollow whose outer peripheral surface is in contact with the inner peripheral surface of the body on one side and whose outer peripheral surface is in contact with the electrode on the other side so that both ends are opened so that the refrigerant flows inside. The cooling system for a lithium secondary battery according to claim 4. The cooling system for a lithium secondary battery according to claim 4 or 5 , wherein the body is fixed to the electrode terminal by welding. The cooling system for a lithium secondary battery according to any one of claims 1 to 6 , wherein the refrigerant is a fluid. The cooling system for a lithium secondary battery according to claim 7 , wherein the fluid is water or air. The cooling system for a lithium secondary battery according to any one of claims 1 to 8 , wherein the refrigerant pipe is made of a synthetic resin. The synthetic resin, chloroprene rubber (Polychloroprene), acrylonitrile - butadiene copolymer rubber, acrylic rubber, nitrile - is of one or more selected from butadiene rubber and mixtures thereof, according to claim 9 Lithium secondary battery cooling system. The conductive connector is made of copper (Cu), aluminum (Al), platinum (Pt), gold (Au), nickel (Ni), zinc (Zn), cobalt (Co), iron (Fe) and alloys thereof. The cooling system for a lithium secondary battery according to any one of claims 1 to 10, wherein the cooling system is one or more selected from the group consisting of:

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